OFFSET
0,2
COMMENTS
For a guide to related sequences, see A211795.
LINKS
Index entries for linear recurrences with constant coefficients, signature (4,-7,8,-7,4,-1).
FORMULA
a(n)=4*a(n-1)-7*a(n-2)+8*a(n-3)-7*a(n-4)+4*a(n-5)-a(n-6).
G.f.: (1 + 4*x^2 + x^4)/((1 - x)^4 * (1 + x^2)).
MATHEMATICA
t = Compile[{{n, _Integer}}, Module[{s = 0},
(Do[If[2 w == Floor[(x + y + z)/2], s = s + 1],
{w, 0, n}, {x, 0, n}, {y, 0, n}, {z, 0, n}]; s)]];
Map[t[#] &, Range[0, 45]] (* A212747 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, May 28 2012
STATUS
approved